This invention pertains to a combination heat transfer panel and wall shield for use with stoves and other radiant heaters. Due to the limited nature of the supply of fossil fuels, it is apparent that these fuels should be reserved for areas in which they are uniquely useful and most critical. Residential and commercial space heating is not necessarily one of those areas; thus, we have witnessed in recent years interest in exploring alternative systems of harnessing energy for space heating, energy which can be derived economically from inexhaustible or replenishable sources. Such systems include nuclear reactors, geothermal and solar devices, windmills, ocean-wave-mills, etc.
Included in this category of alternative energy systems is the wood or coal burning heater/stove. Although wood is not an inexhaustible source of energy, it is replenishable. The revival of the traditional Franklin iron stove has been accompanied by the development of numerous refined embodiments of the traditional stove. New features include the principles of airtightness, thermostatic control, preheating of combustion air, etc. All such features tend to increase the efficiency of combustion so as to maximize the extraction of useful heat from a given amount of fuel.
Although the recent proliferation of iron and steel heater/stoves may well help to ease the burden on petroleum supplies, their installation in conventional wood-frame structures can present problems of safety and convenience. One fundamental problem is the fact that such radiant heaters must be installed with specific minimum clearances from combustibles, if they are to be installed safely. Such clearances can exceed three feet in some cases. This means that the floor space behind such a stove can be virtually useless to the home owner, floor space for which he has paid dearly.
Although radiant heaters are most effective when installed in the middle of a room, the vast majority of installations are not of this type; rather, for aesthetic or practical reasons, the heaters are placed as close as possible to walls or corners. One negative effect of this type of installation, from an efficiency point of view, is that a significant portion of the heat which is radiated from the rear of the stove is absorbed by the back wall and perhaps lost to the outdoors. Some manufacturers design their stoves with steel baffles attached to the rear of their units in order to minimize the amount of radiant heat produced there. Although reduced clearances can be achieved in this manner, it is clear that such a baffled unit produces less total heat than does an unbaffled stove and thus runs counter to the aim of extracting a maximum amount of heat from a given amount of fuel.
Prior art directed toward distance reduction for radiant heaters has for the most part been restricted to specified procedures of field masonry. For example, brick walls are constructed with carefully maintained air spaces behind them to insure a free flow of cool air along the back side. One drawback to this method is the cost involved--in some cases additional footings are required to carry the load of the additional masonry. In many instances such footings are not feasible.
Another method of distance reduction involves the use of prefabricated steel wall panels, hollow sheet metal pans filled with insulation. Whether or not this method of wall protection is truly effective, from a safety point of view, these panels do suffer from the standpoint of aesthetics.
Other methods include the use of various factory-made precast cement panels which are installed with spacers to insure the free flow of cool air on the backside. In various ways, these panels all suffer from problems of weight, cost, inconvenience, and aesthetics.
It is a purpose of this invention to provide economical, convenient, aesthetically pleasing, and functional protective coverings for combustible walls, when these walls are exposed to sources of high radiant heat.
In addition to its function of protecting combustible surfaces, another primary function is to provide an effective means of utilizing heat energy from a radiant heat source and redirecting or converting it in such a manner that it proves most useful for the purpose of heating space.
Another important function of the device described herein is that of utilizing heat that normally is absorbed and lost by the walls located directly behind radiant heaters.
Still a further purpose of the invention is to provide a combination heat transfer panel and wall shield for use with stoves and other radiant heaters which is simple in construction, efficient in operation, low in cost, easily maintained, and attractive in appearance.
The hereindescribed apparatus accomplishing the foregoing and other objects of the present invention broadly comprises a case adapted for location either against, or in spaced relation to, a structural wall behind a stove or other radiant heater. The case comprises a base, a header and side panels.
The front of the case facing the heater has a central opening permitting the entrance of radiant heat. At its lower end preferably, or, alternatively, at the sides, it is provided with a cold air inlet or inlets. At its upper end it is provided with a hot air exhaust.
Curtains hang from the header and are arranged substantially parallel to each other in the plane of the case in spaced relation to each other as required to provide first and second convection chambers communicating with the cold air inlet and the hot air exhaust. The outermost curtain preferably is adjustable between a first position in which it absorbs the radiant heat, transferring it to the convection chambers, and a second position in which it reflects the radiant heat away from the interior of the case. Conduit means may be associated with the cold air inlet and the hot air exhaust for drawing cold air from, and circulating hot air to, selected space areas.